1. Technical Field
Various embodiments of the present disclosure generally relate to a semiconductor memory device and a method of operating the same, and more particularly, to a program operation of the semiconductor memory device.
2. Related Art
Memory devices are classified into a volatile memory device and a nonvolatile memory device.
The nonvolatile memory device may maintain data stored therein even when supply of power is interrupted, although the read and write speeds of the nonvolatile memory device are relatively low compared to those of the volatile memory device. Therefore, the nonvolatile memory device is widely used for portable electronic devices so as to store data that must be maintained regardless of supply of power.
According to a method of storing data, nonvolatile memory devices may be classified into a read-only memory (ROM), a mask ROM (MROM), a programmable ROM (PROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a phase-change random access memory (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FRAM), etc.
Among the nonvolatile memory devices, the flash memory device may have a two-dimensional structure in which cell strings are horizontally arranged on a semiconductor substrate, or a three-dimensional structure in which cell strings are vertically arranged on a semiconductor substrate. The three-dimensional memory device is a device which is devised to overcome a limitation in the degree of integration of the two-dimensional memory device and may include a plurality of memory cells which are vertically stacked on a semiconductor substrate.